What's the difference with using is and == in conditionals?

Question

Code:
if a is None:
# Code

if a == None:
# Code

Answer 1

@Ole113
That doesn't answer my question -_-

Answer 2

You use == when your comparing something and use = when your assigning something.

Answer 3

https://stackoverflow.com/questions/1504717/why-does-comparing-strings-in-JUMP_LINK__&&__python__&&__JUMP_LINK-using-either-or-is-sometimes-produce

Read the 7th answer
Hope this helps.